Method of providing power with essentially nonaqueous emulsions

ABSTRACT

AN ESSENTIALLY NONAQUEOUS, THIXOTROPIC EMULSION OF (1) AN EMULSIFIABLE OIL AND (2) A NONOILY, NONAQUEOUS MATERIAL, THE EMULSION CONTAINING IN THE INTERNAL PHASE AT LEAST 80% OIL BY VOLUME OF THE TOTAL EMULSIONS; METHODS OF PREPARING THE EMULSION; AND USES THEREFOR, PARTICULARLY AS FUELS, INCLUDING THEIR USE AS A SOURCE OF POWER IN ENGINES NORMALLY CAPABLE OF BURNING THE OIL PHASE, SUCH AS IN JET, ROCKET, DIESEL, ETC., ENGINES INCLUDING FUEL INJECTIONN ENGINES, SUCH AS AN INTERNAL COMBUSTION ENGINE, FOR EXAMPLE EMPLOYED IN LANDCRAFT, WATERCRAFT, AIRCRAFT, ETC.

United States Patent Office 3,613,372 Patented Oct. 19, 1971 3,613,372METHOD OF PROVIDING POWER WITH ESSEN- TIALLY NONAQUEOUS EMULSIONSKenneth J. Lissant, St. Louis, Mo., assignor to Petrolite Corporation,Wilmington, Del.

No Drawing. Original application May 10, 1967, Ser. No. 637,332, nowPatent No. 3,539,406, dated Nov. 10, 1970. Divided and this applicationMar. 23, 1970, Ser. No. 22,052

Int. Cl. C06d /10; C101 7/02 US. Cl. 60216 10 Claims ABSTRACT OF THEDISCLOSURE This application is a divisional application of copendingapplication Ser. No. 637,332, now US. Pat. No. 3,539,406 granted on Nov.10, 1970, which is a continuation-in-part of the following copendingpatent ap plications:

Related application Serial No. Filed Title and other comments 286,877May 20, 1963. Stable Emulsions... Now abandoned. 302,001 Aug. 14, HybridFuels 11..... Now US. Pat. No.

1963. 3,396,537 granted on Aug. 13, 1968. 302,177 Aug.3l4, Hybrid FuelsI. Now abandoned.

196 541,738 Apr. 11, Method of Resolv- US. Pat. No.

1966. ing Thixotropic 3,328,418 granted Jet and Rocket on Apr. 16, 1968Emulsions.

547,581 May 4, 1966 Hybrid Fuels 1...... Continuation of SN.

302,177 and now U.S. Pat. No. 3,352,109, Nov. 14, 1967.

Now U.S. Patent 565,702 July 18, Thixotropic Oil-in- Water Emulsion No.3,490,237 Fuels. granted on January 599,332 Oct. 19, Stable Emulsions...Continuation-in- 1066. Part of S.N.

286,877 and now abandoned. 411,103 Nov. 13, Emulsions Now abandoned.

1964. Preparation.

These applications which are by reference incorporated into the presentapplication relate to stable, viscous, thixotropic emulsions and to theuses, preparation, etc., of these emulsions. These applications describeemulsions containing emulsified oily and non-oily phases with particularemphasis on aqueous emulsions.

The present invention relates to stable, viscous, thixotropic emulsionsof the type described in these applications, with the further provisothat the non-oily phase be essentially non-aqueous.

Where water is employed in emulsions, it may create certain problems.For example, water is non-combustible, fosters problems in corrosion andbacterial action, has a relatively high freezing point which is oftentroublesome under conditions of use, etc. Although these problems may bealleviated by employing various additives such as antifreeze,anti-corrosive, anti-bacterial additives, etc., the use of suchadditives may be eliminated and/or reduced by omitting essentially allwater. Whereas non-oily, essentially non-aqueous emulsions are alsodisclosed in the above patent applications, the present applicationrelates to specific embodiments of such non-aqueous emulsions.

Thus, the present invention relates to essentially nonaqueous highinternal phase emulsions; to emulsified fuels such as rocket and jetfuels, diesel fuels, turbine fuels, internal combustion engine fuels,etc., and to the uses thereof. More particularly this invention relatesto such fuels having the characteristics of both liquid and solid fuels(i.e. they are hybrid solid-liquid fuels). Still more particularly thisinvention relates to essentially non-aqueous hybrid solid-liquid fuelswhich are especially prepared, high internal phase, emulsions of onecombustible material and a second combustible and/or volatile materialwhich is immiscible in said first combustible material, said emulsionbeing prepared by means of an emulsifying agent which is capable offorming an emulsion having the characteristics of a solid fuel when atrest and a liquid fuel when force is exerted on it, such as by the shearof pumping, mixing, etc. This invention also relates to said hybridfuels containing certain finely divided solids suspended therein, suchas for example, metals, salts, etc.

Among other things, it has been found that when liquid fuels aresubjected to creases or military action or exposed to firearms or othermeans of ignition under fire power, serious fires and explosions oftenresult. However, when emulsified fuels are subjected to crashes or tofirearms or other fire power, the danger from serious fires andexplosions is substantially reduced or eliminated. This is true ofstorage tanks, aircraft and jets, helicopters, land vehicles, watervehicles, etc.

The term oily phase, as herein employed is intended to include a vastnumber of substances, both natural and artificial, possessing widelydifferent physical properties and chemical structures. All of thesubstances included within this term are practically insoluble in water,and in the non-oily phase employed possess a characteristic greasy touchand have a low surface tension. These include the animal oils of bothland and sea animals; vegetable oils, both drying and non-drying;petroleum or mineral oils of various classes, including those of openchain hydrocarbons, cyclic hydrocarbons or cycloparaflins, with orwithout the presence of solid paraflins and asphalts and various complexcompounds, and which may or may not contain sulphur or nitrogenousbodies; resin oils and wood distillates including the distillates oftrupentine, rosin spirits, pine oil, and acetone oil; various oils,obtained from petroleum products, such as gasolenes, naphthas, gas fuel,lubricating and heavier oils; coal distillate, including benzene,toluene, xylene, solvent naphtha, cresote oil and anthracene oil andethereal oils.

Furthermore, the presence of the usual amounts of anti-knock compoundsor other conventional fuel additives in the oil does not adverselyaflect the usefulness of the oil for our purposes.

The choice of oily phase materials is not limited to hydrocarbons sincesynthetic esters, natural esters, and the like may be employed in thepreparation of useful emulsions. Tung oil, oiticica oil, castor oil,linseed oil, poppyseed oil, soyabean oil, animal and vegetable oils suchas cottonseed oil, corn oil, fish oils, walnut oils, pineseed oils,olive oil, coconut oil, degras, and the like, may also be used.

Practically, the choice of a liquid hydrocarbon for use in jet androcket engine is based largely on availability and cost, and on thisbasis a petroleum hydrocarbon in the gasoline-kerosene range is thepreferred material. Generally either liquid oxygen or fuming nitric acidis used with it as the oxidizer. Whenever the latter is used,practically all of the nitrogen in the acid, under proper burningconditions, appears in the combustion products as nitrogen gas.Aliphatic hydrocarbons from petroleum (gasoline, kerosene) are thecheapest and most abundant liquid fuels for rockets. The simpleraromatic hydrocarbons (benzene, toluene) are also abundant, have higherdensities, and in general give more thermal energy per pound oncombustion so that they produce somewhat more thrust per pound of fuel.Aliphatic hydrocarbons, from the standpoint of structure and heat ofcombustion, could be expected not to differ appreciably one from anotherin the energy they could contribute to a jet motor. Unsaturatedhydrocarbons which are endothermic (that is, which have negative heatsof formation) will, of course, liberate this heat during combustion andcontribute to higher exhaust velocities. The highest calculated value ofspecific impulse for a hydrocarbon burned with oxygen is fordiacetylene, HCECCECH, which gives 271 pound-seconds per pound. This isthe highest that can be expected from any carbonaceous fuel burned withliquid oxygen at 300'p.s.i.a. A more usual value (that for normaloctane) is about 240 pound-seconds per pound.

The non-oily, non-aqueous phase employed herein is one which possesses acohesive energy density number in excess of about 10, whereashydrocarbons typically possess values of less than about 10.

Cohesive energy density is the quotient of the molar heat ofvaporization and the molar volume. The cohesive energy density (C.E.D.)is the amount of energy necessary to separate one ml. of liquid into itsmolecules. Conversely, the C.E.D. is the energy which holds 1 ml. ofliquid together.

The following compounds have a C.E.D. number of about or greater.

The C.E.D. number is defined as /C.E.D. and is usually employed incomparisons and calculations.

The following is a list of compounds having a C.E.D. number of about 10or greater. In general, there should be sufiicient difference in theC.E.D. numbers of each phase to make a suitable emulsion.

C.E.D. No.: Description 9.92 N,N-diethyl acetamide. 9.95 1,4-dioxane.10.0 Acetone. 10.0 Carbon disulfide. 10.0 Dioxane. 10.0 Ethylamine. 10.0Nitrobenzene. 10.0 Propionic anhydride. 10.1 Acetic acid. 10.1 t-Butylalcohol. 10.1 Methyl formate. 10.1 Polymethyl chloroacrylate. 10.2m-Cresol. 10.2 Cyclohexanol. 10.2 Methyl formate. 10.2 Methyl iodide.10.2 Propionitrile. 10.2 Pyridine. 10.3 Acetaldehyde. 10.3 Aniline. 10.3Carbon disulfide. 10.3 Isobutyric acid. 10.3 Methylene chloride. 10.3n-Octyl alcohol. 10.4 Sec-butyl alcohol. 10.4 Cyclopentanone. 10.41,2-dibromomethane. 10.4 Methyl formate. 10.5 Acrylonitrile. 10.5Bromoform. 10.5 n-Butyric acid. 10.5 Tris-(dimethylamido) phosphate.10.5 Isobutyl alcohol. 10.56 Cellulose dinitrate. 10.6 Acetic anhydride.

10.6 tert-Butyl alcohol.

C.E.D. No.: Description 10.6 N,N-diethylforamide. 10.6 n-Heptyl-alcohol.10.6 Propionitrile. 10.7 n-Butyl alcohol. 10.7 n-Hexyl alcohol. 10.7Polyglycolterephthalate. 10.7 Polymethacrylonitrile. 10.7 Pyridine. 10.8Benzyl alcohol. 10.8 N,N-dimethylacetamide. 10.9 Amyl alcohol. 10.9Cellulose diacetate. 11.0 N-acetylpiperidine. 11.0 Dichloroacetic acid.11.0 Ethyl cyanoacetate. 11.0 Di-methylmalonate. 11.1 Cyclobutanedione.11.1 Dimethyl oxalate. 11.1 Ethyl oxide. 11.2 Furf-ural. 11.2 Methylamine. 11.3 Dipropyl sulphone. 11.4 N-acetylpyrrolidine. 11.4 n-Butanol.11.4 NNN'N-tetramethyloxamide. 11.5 Bromine. 11.5 N-formylpiperidine.11.5 Isopropanol. 11.6 N-acetylmorpholine. 11.7 Acetonitrile. 11.8 Allylalcohol. 11.8 Methylene iodide. 11.9 Acetonitrile. 11.9 N-propylalcohol. 12.0 2:3-butylene carbonate. 12.1 Acetonitrile. 12.1 Dimethylformamide. 12.1 Dimethyltetramethylene sulphone. 12.1 Formic acid. 12.1Hydrogencyanide. 12.2 Ethylene chlorhydrin. 12.4 Methylene glycollate.12.4 Nitromethane. 12.5 Diethyl sulphone. 12.5 Dimethyl phosphite. 12.5Methyl propyl sulphone. 12.6 Chloroacetonitrile. 12.6 Osmium tetroxide.12.7 e-Caprolactam. 12.7 Ethyl alcohol. 12.7 Nitro methane. 12.9,B-Methyltetramethylene sulphone. 13.0 N-formylmorpholine. 13.1NN-dimethylnitroamine. 13.3 Butyrolactone. 13.3 Propiolactone. 13.31:2-propylene carbonate. 13.4 Methyl ethyl sulphone. 13.4 'y-Pyrone.13.6 Maleic anhydride. 13.6 'y-Piperidone. 13.9 Dimethyl sulfoxide. 14.3Methyl alcohol. 14.3 Tetramethylene sulphone. 14.4 EtOI-I 14.4 Methanol.14.6 Dimethylsulphone. 14.6 Ethylene glycol. 14.7 Ethylene carbonate.14.7 v-Pyrrolidone. 14.8-15.2 Polyacrylonitrile. 15.1 Malonylnitrile.15.4 Succinic anhydride. 16.3 Ammonia.

24.2 Water.

In general, in addition, the non-oily, non-aqueous phase possesses thefollowing characteristics:

(1) Is liquid over the range of use.

(2) Is essentially immiscible with the internal phase and/or is capableof forming a distinct separate phase.

(3) Is capable of dissolving the emulsifier so as to concentrate it atthe liquid interfaces to prevent coalescence of the internal phase.

(4) Is itself a solvating agent, or contains a solvating agent ormixture of solvating agents, for the emulsifier.

Thus, the non-oily, non-aqueous phase contains one or more non-oilymaterials and an emulsifier dissolved therein, said non-oily phase beingessentially insoluble in the oily phase and said emulsifier beingcapable of preparing and maintaining a stable, viscous, thixotropic orpsuedoplastic emulsion.

Stated another way, the non-oily phase may be looked upon as having twofunctions:

(1) Is essentially immiscible in the oily phase and/or is capable offorming a distinct separate phase.

(2) Is itself a solvent for the emulsifier, or containing a solventcapable of dissolving the emulsifier so as to concentrate the emulsifierat the interface to prevent coalescence of the internal phase.

The non-oily phase may be of (1) the polar protic type as illustratedby:

Alcohols, e.g. methanol, ethanol, propanol, etc.

Glycols, e.g. ethylene glycol, propylene glycol, etc.

Polyglycols, e.g. H(OA),,H where A is alkylene and n is an integer forexample 1-10 or greater, for example diethyleneglycol,triethyleneglycol, dipropyleneglycol, tripropyleneglycol, etc.,

polyalcohols, aldehydes, polyaldehydes, etc.; and (2) of thepolaraprotic type as illustrated by N-alkylcarboxylamides such asN,N-dialkylcarboxylamide's such as N,N- dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-dimethylacetamide, etc., andclosely related compounds such as formamide, N-methyl formamide,N,N-dimethyl methoxy acetamide, etc.

Other illustrative solvents are dimethyl sulfoxide, dimethyl sulfone,N-methyl-Z-pyrrolidone, tetramethylurea, pyridine, hexamethylphosphoramide, tetramethylene sulfone, butyrolactone, nitroalkanes suchas nitromethanes, nitroethanes, etc.

Mixtures of a variety of polar aprotic solvents can also be employed, aswell as polar aprotic solvents in combination with polar proticsolvents.

In general, the techniques described in the above applications can beemployed in preparing the non-aqueous emulsions of this invention. Theseemulsions are prepared by employing any suitable emulsifying agent.Although oxyalkylates are preferred, other types of suitable emulsifierscan also be employed including the anionic, cationic, non-ionic andampholytic demulsifiers.

By using the means of selecting suitable emulsifiers described in thepatent applications referred to herein, one can select and employemulsifiers, for example, of the following types:

(I) ANIONIC (A) Carboxylic acids (B) Sulfuric esters (sulfates) (1)Sulfate joined directly to hydrophobic group.

(a) Hydrophobic group contains no other polar ether,

structures (sulfated alcohol and sulfated olefin type).

(b) Sulfuric esters with hydrophobic groups containing other polarstructures (sulfated oil type).

Sulfate group joined through intermediate linkage.

(a) Ester linkage (Arctic Syntex M. type).

(b) Amide linkage (Xynomine type).

(c) Ether linkage (Triton 770 type).

(d) Miscellaneous linkages (e.g., oxyalkylimidazole sulfates).

(C) Alkane sulfonic acids Sulfonic group directly linked (a) Hydrophobicgroup bears other polar substituents (highly sulfated oil type). Chloro,hydroxy, acetoxy, and olefin sulfonic acids (Nytron type).

(b) Unsubstituted alkane sulfonic acids (MP 189 type: also cetane sulfoacid type).

(c) Miscellaneous sulfonic acids of uncertain structure, e.g., oxidationproducts of sulfurized olefins, sulfonated rosin, etc.

(2) Sulfonic groups joined through intermediate linkage.

(a) Ester linkage.

(1) RCOOXfiSO' H (Igepon AP type). (2) ROOCXSO' H (aerosol andsulfoacetate type).

(b) Amide linkage.

(l) RCONHXSO H (Igepon T type). (2) RNHOCXSO H ('sulfosuccinamide type).

(c) Ether linkage (Triton 720 type).

(d) Miscellaneous linkages and two or more linkages.

(D) Alkyl aromatic sulfonic acids (1) Hydrophobic group joined directlyto sulfonated aromatic nucleus (subclasses on basis of nature ofhydrophobic group. Alkyl phenols, terpene, and rosin-aromaticcondensates, alkyl aromatic ketones, etc.)

(2) Hydrophobic group joined to sulfonated aromatic nucleus through anintermediate linkage.

(a) Ester linkage (sulfophthalates, sulfobenzoates). (b) Amide andimidie linkages.

(1 RCO'NHArSO H type. 2) Sulfobenzamide type. (c) Ether linkage (alkylphenyl ether type). (d) Heterocyclic linkage (Ultravon type, etc.). (e)Miscellaneous and two or more links.

(E) Miscellaneous anionic hydrophilic groups (1 Phosphates andphosphonic acids. (2) Persulfates, thiosulfates, etc.

(3) Sulfonamides.

(4) Sulfamic acids, etc.

(II) CATIONIC (A) Amine salts (primary, secondary, and tertiary amines)(1) Amino group joined directly to hydrophobic group.

(a) Aliphatic and aromatic amino groups. (b) Ar)nino group is part of aheterocycle (alkaterge type (2) Amino group joined through anintermediate link.

(a) Ester link. (b) Amide link. (0) Ether link. ((1) Miscellaneouslinks.

(B) Quaternary ammonium compounds (1) Nitrogen joined directly tohydrophilic group. (2) Nitrogen joined through an intermediate link.

(a) Ester link. (b) Amide link. (0) Ether link. (d) Miscellaneous links.

(C) Other nitrogenous bases (1) Non-quaternary bases (classified asguanidine, thiuronium salts, etc.). (2) Quaternary bases.

(D) Non-nitrogenous bases (1) Phosphonium compounds. (2) Sulfoniumcompounds, etc.

(III) NON-IONIC (A) Ether linkage to solubilizing groups. (B) Esterlinkage.

(C) Amide linkage.

(D) Miscellaneous linkages.

(E) Multiple linkages.

(IV) AMPHOLYTIC (A) Amino and carboxy: (1) Non-quaternary. (2)Quaternary. (B) Amino and sulfuric ester: (1) Non-quaternary. (2)Quaternary. (C) Amine and alkane sulfonic acid. (D) Amine and aromaticsulfonic acid. (E) Miscellaneous combinations of basic and acidicgroups.

Although any suitable emulsifier can be employed, the emulsifiers mostusually employed in the practice of this invention are generally knownas oxyalkylated surfactants or more specifically polyalkylene ether orpolyoxyalkylene surfactants. Oxyalkylated surfactants as a class arewell known. The possible sub-classes and specific species are legion.The methods employed for the preparation of such oxyalkylatedsurfactants are also too well known to require much elaboration. Most ofthese surfactants contain, in at least one place in the molecule andoften in several places, an alkanol or a polyglycolether chain. Theseare most commonly derived by reacting a starting molecule, possessingone or more oxyalkylatable reactive groups, with an alkylene oxide suchas ethylene oxide, propylene oxide, butylene oxide, or higher oxides,epichlorohydrin, etc. However, they may be obtained by other methodssuch as shown in US. Pats. 2,588,771 and 2,596,0913, or byesterification or amidification with an oxyalkylated material, etc.Mixtures of oxides may be used as well as successive additions of thesame or different oxides may be employed. Any oxyalkylatable materialmay be employed. As typical starting materials may be mentioned alkylphenols, phenolic resins, alcohols, glycols, amines, organic acids,carbohydrates, mercaptans, and partial esters of polybasic acids. Ingeneral, if the starting material is water or non-oily soluble, it maybe converted into an oil-soluble surfactant by the addition ofpolypropoxy or polybutoxy chains. If the starting material isoil-soluble, it may be converted into a water or non-oily solublesurfactant by the addition of polyethoxy chains. Subsequent additions ofethoxy units to the chain tend to increase the water or non-oilysolubility, while subsequent additions of high alkoxy chains tend toincrease the oil solubility. In general, the final solubility andsurfactant properties are a result of a balance between the oil-solubleand water or non-oily soluble portions of the molecule.

In the practice of this invention it has been found that emulsifierssuitable for the preparation of high internal phase ratio emulsions maybe prepared from a wide variety of starting materials. For instance, ifone begins with an oil-soluble material such as a phenol or a long chainfatty alcohol and prepares a series of products by reaction withsuccessive portions of ethylene oxide, one finds that the members of theseries are successively more water or non-oily soluble. One finds alsothat somewhere in the series there will be a limited range where theproducts are useful for the practice of this invention.

Similarly it is possible to start with water or a water or non-oilysoluble material such as polyethylene glycol and add, successively,portions of propylene oxide. The members of this series will beprogressively less water-soluble and more oil-soluble. Again there Willbe a limited range where the materials are useful for the practice ofthis invention.

In general, the compounds which would be selected for testing as totheir suitability are oxyalkylated surfactants of the general formulawherein Z is the oxyalkylatable material, R is the radical derived fromthe alkylene oxide which can be, for example, ethylene, propylene,butylene, epichlorohydrin and the like, It is a number determined by themoles of alkylene oxide reacted, for example 1 to 2000 or more and m isa whole number determined by the number of reactive oxyalkylatablegroups. Where only one group is oxyalkylatable as in the case of amonofunctional phenol or alcohol ROH, then m=l. Where Z is water, or aglycol, m=2. Where Z is glycerol, m=3, etc.

In certain cases, it is advantageous to react alkylene oxides with theoxyalkylatable material in a random fashion so as to form a randomcopolymer on the oxyalkylene chain, i.e. the [(-OR) OH] chain such asAABAAABBABABBABBA In addition, the alkylene oxides can be reacted in analternate fashion to form block copolymers on the chain, for example-BBBAAABBBAAAABBBB- BBBBAAACCCAAAABBBB- where A is the unit derived fromone alkylene oxide, for example ethylene oxide, and B is the unitderived from a second alkylene oxide, for example propylene oxide, and Cis the unit derived from a third alkylene oxide, for example, butyleneoxide, etc. Thus, these compounds include terpolymers or highercopolymers polymerized randomly or in a block-wise fashion or manyvariations of sequential additions.

Thus, (OR) in the above formula can be written -A B C or any variationthereof, where a, b, and c are zero or a number provided that at leastone of them is greater than zero.

It cannot be overemphasized that the nature of the oxyalkylatablestarting material used in the preparation of the emulsifier is notcritical. Any species of such material can be employed. By properadditions of alkylene oxides, this starting material can be renderedsuitable as an emulsifier and its suitability can be evaluated byplotting the oxyalkyl content of said surfactant versus its performance,based on the ratio of the oil to water which can be satisfactorilyincorporated into water as a stable emulsion. By means of such a testingsystem any oxyalkylated material can be evaluated and its properoxyalkylation content determined.

As is quite evident, new oxyalkylated materials or other emulsifierswill be constantly developed which could be useful in preparing theseemulsions. It is therefore not only impossible to attempt acomprehensive catalogue of such compositions but to attempt to describethe invention in its broader aspects in terms of specific chemical namesof the components used would be too voluminous and unnecessary since oneskilled in the art could by following the testing procedures describedherein select the proper components. This invention lies in the use ofsuitable emulsifiers in preparing the compositions of this invention andtheir individual composition is important only in the sense that theirproperties can effect these emulsions. To precisely define each specificsurfactant useful as an emulsifier in light of the present disclosurewould merely call for chemical knowledge within the skill of the art ina manner analogous to a mechanical engineer who perscribes in theconstruction of a machine the proper materials and the proper dimensionsthereof. From the description in this specification and with theknowledge of a chemist, one will know or deduct with confidence theapplicability of emulsifiers suitable for this invention by means of theevaluation tests set forth herein. In analogy to the case of machinewherein the use of certain materials of construction or dimensions ofparts would lead to no practical useful result, various materials willbe rejected as inapplicable where others would be operative. One canobviously assume that no one will wish to make a useless composition orwill be misled because it is possible to misapply the teachings of thepresent disclosure in order to do so. Thus, any emulsifier that canperform the function stated herein can be employed.

REPRESENTATIVE EXAMPLES OF Z As the base oxyalkylated material (Ex:Alkylene oxide block polymer) i X=O, -s, CH fi-, etc.

0 I 12 RSCH O 13 RP 04H- i 16 Rug-sono- 17 R.. -so2N= 0 H 18 R(iN N 19Pol ol-derived (Ex? glycerol, glucose, pentaenthrytol) 20 Anhydrohexitaeor anhydrohexide derived (Spans and Tweens) 21 Polycarboxylic derived 22(-(EHCH -O-h amine Examples of oxyalkylatable materials derived from theabove radicals are legion and these, as well as other oxyalkylatablematerials, are known to the art. A good source of such oxyalkylatablematerials, as well as others, can be found in Surface Active Agents andDetergents, vol. 1 and 2, by Schwartz et al., Interscience Publishers(vol. 1, 1949-vol. 2, 1958) and the patents and references referredtotherein.

In general, the base oxyalkylatable material is tested for solubility inwater or the particular non-oily material employed or toluene, or anyother suitable oily material. If it is water or nonoily soluble it isoxyalkylated with propylene or butylene oxide until it is just oilsoluble, with representative samples being collected as its oxyalkylatecontent is increased. If the oxyalkylatable material is oilsoluble, thenit is oxyalkylated with ethylene oxide until it is just water ornon-oily soluble, with representative samples being collected as itsoxypropylation or oxybutylation content is increased. These samples aresimilarly tested. This procedure can thereupon be repeated with anotheralkylene oxide until opposite solubility is achieved, i.e. if thematerial is water or non-oily soluble it is oxypropylated oroxybutylated until it is oil-soluble. If the prior oxypropylated oroxybutylated material is oilsoluble, it is treated with ethylene oxideuntil it is water or non-oily soluble. This can be repeated in stageseach time changing the material to one of opposite solubility by using ahydrophile oxide (i.e. EtO) for an oil-soluble material and a hydrophobeoxide (i.e. PrO or BuO) for water solubility. The same procedure andtests are employed at each stage, proceeding each time to oxyalkylationto opposite solubility.

Although the amount of oxyalkylated material present in the emulsion isgenerally 0.05-5 volume percent, such as 0.1 to 4%, but preferably 0.2-3larger amounts can also be employed if desired. However, economicsgenerally restrict the amount employed to the ranges indicated.

The exact range which is useful for the practice of this invention willvary with the starting emulsifier base and the sequence of alkyleneoxides used to achieve the polyalkylene ether chains. It should also benoted that materials useful in the practice of this invention can bemade by other well-known methods besides oxyalkylation such as theesterification of a polyalkylene ether alcohol, reaction of carboxylicacids with oxyalkylated amines, etc. Thus, the term oxyalkylatedincludes any means of attaching the oxyalkyl group to a molecule. Anymethod of attaching oxyalkyl groups to a molecule can be employed.

It has also been found that the optimum range of effectiveness for anyparticular emulsifier series will vary with the particular oil phase andalso with the composition of the non-oily phase which is employed.

To illustrate the variety of materials that may be used as emulsifiersin the practice of this invention the following examples are presented.It should be noted that these examples are simply illustrative andshould not be construed as imposing limitations on the scope of theinvention.

Emulsifier No. 1

This emulsifier was prepared in the same manner as Examples 9-21 ofapplication Ser. No. 302,177, filed Aug. 14, 1963, except that mixedalkylphenol having 15 to 20 carbons in the alkyl group was oxyalkylatedwith 3.80 parts by weight of ethylene oxide.

The final product was a waxy brown solid at room temperature.

Emulsifier No. 2

This emulsifier was prepared in the manner of Example 1 of Ser. No.302,177 by oxyalkylating one part by weight of n-decanol and with 1.96parts by weight of propylene oxide followed by 2.61 parts by weight ofethylene oxide.

Emulsifier No. 3

This emulsifier was prepared in the manner of Example 34 of Ser. No.302,177 by reacting one part of p-tertiarybutyl phenol with 15.40 partsby weight of propylene oxide 12 phase and mixing it with 2-4 parts byvolume of the emulsifier. With efficient mixing, the oily phase isslowly added in small amounts allowing the mixer ample time toincorporate the oily phase into the emulsion. As the amount of materialin the mixture increases, mixing ac- 9 ig p 3231 gig by Welght ofethylene oxlde to tion is more efiicient and further additions are madeyle a W 1 e y s 1 more rapidly. When the mixer will no longer produce anEmulsifier No. 4 emulsion with no free oily phase, the limit of theemul- This emulsifier was prepared in the manner of Ser. No. 1Sconslcllelgld g i t d b re of dinonyl phenol was Oxyalkylated with partsby tiveness in thi particul ar oily nonoily sy stem under conwelght ofethylene oxide to yield a pasty brown material. Sideration. For example,a nonoily Soluble base is Emulsifier No. 5 alkylated with propyleneoxide (PrO) or butylene oxide This emulsifier is a commercial productdesignated 5 BuO) 8 r f' g lsjoluble i i q Tween-40. It is apolyoxyethylene sorbitan monofg 1 3. ase a palmitate, which is clear,light amber in color, and is yene OX1 e um I 18 none] y Sou e an51mllarly tested to select the optlmum emulslfier. water soluble.

Emulsifier N0. 6 A test, such as outhned 1n Ex. 77 of Ser. No. 302,17720 filed Aug. 14, 1963, may be used on any other test that ThlSemulsifier IS a Commerclal P P deslgnat'ed accurately reflects theproposed method of preparing the Triton QS15. It is an oxyethylatedsod1um salt, Contalndesired emulsion. The results of the test are thenplotted ing both anionic and cationic centers. The material is an on amulti-dimensional noncommutati-ve composition anhydrous, water-solubleliquid. space that represents the family of materials being used.Emulsifier Na 7 Such tests and plots reveal the existence of an optlmumperformance reg1on 1n the compositlon space. T1115 18 a commerclalProduct sig a d H 0dag SVO-9. The following example illustrate thepreparation of non- It 8 s descrlbfid as Polysorbate 0, Which s allaqueous emulsions of this invention. These emulsions were vegetable baseester. The ester is a water-soluble yellow prepared i th manner f E l 77of S 302 liquid. 177 except the particular nonoily phase specified isem- The following emulsifier 15 not oxyalkylated, 1.e., the ployed inplace of ter specified in Example 77. Starting material was not reactedWith ethylene Oxide, To save repetitive details the emulsions preparedherein propylene oxide, etc., or with any material which would areoutlined in the following table.

TABLE II Internal phase External phase Volume percent Emul- Emulsiofsion fier total No. Material Ml. Number Ml. Material Ml. emulsion 1Dirnethylsulfoxide 9. 75 1 3.25 JP. 4 490 97.42 2 ..do 9. 75 1 3.25Kerosine. 490 97.42 3 {Ethylene glycol 8.35 1 2.60 ..do 490 96.55

Methanol (C.P.) ..1.. 5.80 2 5 4 {Ethylene glycol... 7

Methanol (C.P.) 5... Dimethylacetamid 11.25 3 6 Ethylene glycol .1 16.127 {Ethyleneglycol 8.35 1 Methanol (C.P.) 5.80 2 8 Ethylene glycol 8.25 1Ethanol (C.P.)...... 1 7.80 2 9 {Dimethyl sulfoxide. 1

Ethylene glycol. 10 {Ethylene glycol. Methanol .1.. 11 {Ethylene glycol.

1 ethanol.. 5.02s 6 2.112 JP. 4...... 500 96.24 Dimethylsulfoxide 1.9.75 5 4.00 JP.4 695 97.47 12 ..{l\'1ethanol(C.P.)... .1 .25 Ethyleneglycol .1 4.00 Nitromethane... 2.07 1 2.23 JP.4. 500 96.0 13 ..{Methanol(c P.) 8.93 2

Ethylene glycol- 7. 21 Nitr0methane.. 2. 0 14 "{Methanol (C.I.) 2. 9

Ethylene glycol 1. 7.21 1.

produce a polyether linkage, which is characteristic of oxyalkylatedmaterials.

Emulsifier No. 8

The above examples describe essentially non aqueous emulsions. Incertain instances it may be desirable to add a small amount of anaqueous component to the emulsion whether in the form of water itself ora solution of other components in water such as acid, bases, etc. Thefollowing examples are presented as illustrations of such emulsionsystems.

The percent of water in the total emulsion of the following examples isminor, for example, about l2% or less, for example, about 1% or less andmay in certain instances be extremely small such as 0.5 to 0.1% or less.

Internal phase External phase Emulsifier Ml. Number N0. M1. MaterialMaterial Dlmethyl formamide.- 15 Ammonium hydroxide (cone). Ethyleneglycol 16 Dimethyl formarnide Methanol (0.1 Water 17 {Dimethylcetarru'de..

Ammonium hydroxide (0011s.). Dimethyl acetamide 20 Ammonium hydroxlde(c0110.).

Although the fact that the essential absence of Water in these emulsionsminimizes problems such as freezing, corrosion, bacterial and relatedactions, etc., which avoid the use of certain additives to correct theseproblems, such additives may be employed where the problems persists orwhere one deems it desirable to employ suc-h additives.

These emulsions can also be prepared on a continuous basis by followingthe procedure described in Ser. No. 411,103 filed Nov. 13, 1966, whichin essence comprises (1) preparing a preformed emulsion of approximatelythe same character as the desired emulsion (2) introducing withsufiicient agitation into the preformed emulsion the internal andexternal phases of the emulsion in such proportions so as to produce thedesired emulsion and (3) withdrawing the emulsion at the desired rate.

By following the procedure described in Ser. No. 411,- 103 andsubstituting the nonoily components described herein in place of water,one can prepare the present emulsions.

The emulsions of the present invention possess the following advantages.

(1) Nonadhesive.They tend not to stick to the sides of the container.Thus hold up in fuel tanks is minimized.

(2) Viscosity.The apparent rest viscosity is greater than 1000 c.p.s.,generally in the range of 10,000- 100,000 or greater. However, under lowshear, they will flow with a viscosity approaching that of the liquidphases. On removal of shear, the recovery to original apparent restviscosity is nearly instantaneous. The hysteresis loop is very small.

(3) Temperature stability.Increased temperature has little effect onviscosity until the critical stability temperature is reached at whichpoint the emulsion breaks into its liquid components. This permits aWide temperature range of operation.

(4) Shear stability.Emulsions may be subjected repeatedly to shearwithout degradation so long as the critical shear point is not reached.At this point the emulsion breaks. However, the critical shear point issufficient- 1y high to permit pumping at high rates.

(5) Quality control.--With these emulsions it is easy to reproducebatches with identical properties due to the absence of any gelstructure.

(6) Metering, heat transfer, and nozzle spray characteristics.Sinceemulsions can be broken with high shear, this can be done at theturbopump, giving completely liquid flow from that point on. This Willpermit metering by conventional means and will preclude laminar flowwith attendant reduction of heat transfer capability, resulting incompletely liquid nozzle flow and combustion characteristics.

Volume percent of total emulsion (7) Solid loading-Emulsions will flowwell even with high solids loading since they have a broad range betweenrest viscosity and viscosity under modest shear.

In contrast to very high volume percent solid loading in gels orslurries which result in a putty, these emulsions can suspend suchsolids in the internal phase while allowing the external phase to governfiowability.

8) Recovery of oily phase.When gelling agents are dissolved in the fuel,distillation is required to recover the original component. Withemulsions, application of high shear or high temperature to break theemulsion, and a subsequent decantation or drawoif operation, is all thatis required. This is significant in considering a storable weaponsystem. It would be a simple matter to exhaust a missile, break the fuelemulsion, and remake it periodically as required.

In some applications it may be desirable to be able to break theemulsion and reclaim the original phases. In such cases advantage may betaken of the effect of extremely high shear. For instance, thickenedfuels of the type encompassed by this invention are easier to transportand less subject to evaporation, ignition, and spillage than fuels inconventional form. Due to their thixotropy they may be pumped withoutdifficulty. They may be broken back to the original fuel by passingthrough a nozzle and allowing the small amount of aqueous phase tosettle out. This is not true of gels which have been made from soaps andother materials currently used for such purposes.

Fuels prepared by the practice of this invention also have utility inapplications where the sloshing of fuels in storage tanks is a problem.Since the fuels are pumpable and yet viscous they may be used in liquidfuel rockets and jets, where the shift of weight concomitant with asudden change in direction will seriously affect the trim of the vessel.The reduced tendency to splash and shift lessens the need for elaboratebulkheads and allows more payload.

In summary, the emulsions of this invention have an apparent restviscosity of about 1,000 to 100,000 or more c.p.s. such as 25,000 to100,000 or more, for example, 40,000100,000, but preferably50,000-100,000 c.p.s. Emulsions have been prepared having apparent restviscosities of about 10,000, 20,000, 30,000, 40,000, 50,000, 60,000,70,000, 80,000, 90,000, 100,000 or greater.

This invention also comprises an emulsion consisting of a minor amountof an external phase and a major amount of an internal phase having afinely divided combustible solid dispersed within it. The choice of thesolid is dictated primarily by specific impulse considerations. Theusual practice of this invention would be to select a combination ofliquid fuels and finely divided solids which are mutually non-reactiveat storage temperatures and which yield potentially the maximum specificimpulse. Specific impulse can be defined by the following equation.

The expression for specific impulse (1 and the equations which lead toit are as follows (Ft=total impulse in lb.-sec. and F=mc/g):

where I =Specific impulse, pounds of thrust per pound weight ofpropellant burned per second.

F=Thrust, lb.

t=Duration of thrust due to burning, sec.

W=Total weight of propellant, lb.

m=Weight of propellant burned per second, lb./ sec.

c=Effective exhaust velocity of propellant gases, ft./sec. actualexhaust velocity of propellant gases in the case of rockets (but not forair-breathing jets), ft./ sec.

g=Acceleration due to gravity, ft./sec.

R'=RM=Universal gas constant, 1544 ft.-lb./(lb.-mole) R=Gas constant perpound weight of propellant gases,

ft.-lb./(lb.) F.).

T =Combustion chamber temperature, R.

M=Average molecular weight of propellant gases.

C =Heat capacity of propellant gases at constant pressure, B.t.u./(lb.)F.).

C =Heat capacity of propellant gases at constant volume,

B.t.u./(lb.) F.).

P =Pressure of propellant gases at nozzle exit, p.s.i.

P =Pressure of propellant gases in combustion chamber,

Having selected the best available combination fuels and solids andhaving calculated the optimum proportion of solids and fuels to be used,one selects a liquid for the external phase that is non-reactive witheither the fuel or the finely divided solid, is immiscible with thefuel, and not a solvent for the solid fuel. Using the methods detailedelsewhere in these specifications, one then selects an appropriateemulsifier for the system. This emulsifier is then dissolved ordispersed in the external phase liquid and the mixture of solid andliquid fuels mixed into this liquid by any of the methods elsewheredescribed.

Examples of combustible solids elements which are of interest whencombined with appropriate liquid fuels are lithium, beryllium, boron,carbon, sodium, magnesium, aluminum, silicon, etc. The hydrides ornitrides of the above elements, when they are solids, may be employed.These are employed as finely divided solids, for example a particle sizeof less than about 200 microns, such as less than about 100 microns, forexample from about 0.5 to 50 microns, but preferably from about 1 tomicrons.

The amount of finely divided solids added to the fuel can vary widely,such as from about 5 to 200 g. or more per 100 volumes of emulsions, forexample from about 10 to 180, preferably from about to 140, but usuallyfrom about to 120.

The following examples are presented in non-limiting examples whichillustrate the practice of this invention in which finely divided solidsare employed.

1 6 EXAMPLE A To the mixing bowl of the Model 3-C Kitchen Aid was added9.75 ml. of the external phase of Example 2 of Table II and 3.25 ml. ofEmulsifier No. 1. This mixture was then stirred until it becamehomogeneous. Four hundred ninety ml. of kerosine was then added slowly,while stirring. The result was a smooth, hazy, viscous emulsion. Thiswas divided into two equal parts. Eighty grams of powdered aluminum wasstirred into one half of the emulsion, resulting in a thick greycomposition. Both the emulsion with the aluminum and the emulsionwithout the aluminum were equally stable.

EXAMPLE B A similar emulsion was prepared in the manner of Example Aexcept that the external phase used consisted of 8.35 ml. ethyleneglycol and 5.80 ml. methanol (OR). The emulsifiers used were 2.60 ml. ofEmulsifier No. 1 and 0.65 ml. of Emulsifier No. 2. The internal phaseconsisted of 490 ml. of kerosine and grams of powdered aluminum.

EXAMPLE C A similar emulsion was prepared in the manner of Example Aexcept that the materials used were 7.40 ml. of ethylene glycol and12.60 ml. of methanol (C.P.) (Emulsion No. 4). The emulsifier used was2.47 ml. Hodag SVO9 (Polysorbate 80). Eighty grams of powdered aluminumwas employed.

EXAMPLE D A similar emulsion was prepared in the manner of Example Aexcept that the materials used were 7.50 ml. dimethylformamide and 2.70ml. concentrated ammonium hydroxide of Emulsion No. 19. The emulsifiersused were 1.25 ml. of Emulsifier No. 2 and 1.25 ml. of Emulsifier No. 4.Eighty grams of powdered aluminum were employed.

EXAMPLE E A similar emulsion was prepared in the manner of Example Aexcept that the materials used were 9.75 ml. of dimethyl acetamide and8.00 ml. concentrated ammonium hydroxide of Emulsion No. 20. Theemulsifiers used were 1.25 ml. of Emulsifier No. 2 and 1.25 ml. ofEmulsifier No. 4. Eighty grams of powdered aluminum were employed.

EXAMPLE F A similar emulsion was prepared in the manner of Example Aexcept that the materials used were 2.07 ml. nitromethane, 8.93 ml.methanol (CR), and 7.21 ml. ethylene glycol. The emulsifiers used were2.23 ml. of Emulsifier No. 1 and 0.56 ml. of Emulsifier No. 2. Fiftygrams of powdered aluminum were employed.

EXAMPLE G A similar emulsion was prepared in the manner of Example D,except that 10 grams of carbon black were employed in place of 80 gramsof powdered aluminum.

EXAMPLE H A similar emulsion was prepared in the manner of Example Aexcept that a small portion of boron was employed in place of 80 gramsof powdered aluminum.

The above examples are employed to illustrate the preparation of theemulsions of this invention containing combustible powdered solids whichcan be employed in jet and rocket fuels. However, it should beunderstood that powdered aluminum and other powdered solids can besimilarly added to other emulsions prepared in accord with thisinvention, for example the emulsions described in the specific examplesdisclosed herein.

The emulsions of this invention can be employed in both mono-propellantand polypropellant systems. The

emulsion can be employed to suspend oxidizing agents in the fuel. Forexample, an inorganic oxidizing agent such as a nitrate or a perchloratemay be incorporated therein in varying amounts.

One can readily prepare emulsions containing about 20% by volume of suchoxidizers as nitrates, such as lithium nitrate, potassium nitrate, orhydrazine nitrate and the like, perchlorates, chlorates, chlorites,hypochlorites, dichromates, chromates and persulfates, such as thepotassium, sodium and ammonium salts. Salts of other metals such ascalcium, magnesium, aluminum and the like may also be employed.

The propellant mixture can comprise the fuel components containingfinely divided oxidizers in proportions preferably such that the fuel ispresent in molal excess i.e. and excess in the amount which would beconsumed by the oxidizer in the propellant mixture would be from about50-90% of that which would be required for complete combustion of thefuel although when desired proportions of oxidizer above the 90% can beemployed, e.g. 100%.

The oxidizers may be of the formula MA where M is the cation such as NHor a metal and Y represents the valency of M. The metal can be one ofthe metals of Group l-A, l-B, II-A, III-A, IV-A and VIII of the PeriodicTable of elements.

For example to use perchlorates as an example M(ClO the perchlorates canbe alkaline metal perchlorates such as the lithium, sodium, potassium,cesium, etc. perchlorates; magnesium, calcium, barium, iron, silver,thalium, etc. perchlorates.

Little is to be gained by a detailed description of the jet and rocketengines in which compositions of this type are burned. Recent details ofthe construction of such engines are not generally available due tosecurity restrictions. A general description of the operation of rocketand jet engines is given in Encyclopedia of Chemical Technologypublished by Interscience Publishers (1951) vol. 6, pages 954-959 underJet Propulsion Fuels and in vol. 11, pages 760-778 under RocketPropellants.

A short description of the operation of jet engines is given in the samepublication on page 954, and of rocket engines on pages 766-767 thereofand elsewhere. Since the compositions of this invention may be pumpedand handled in the same manner as liquids they are used in the sametypes of engines as conventional liquid fuels. They possess the uniqueadvantages of high density (due to the incorporated solids), stability,restartability, and high specific impulse.

Having thus described my invention what I claim as new and desire toobtain by Letters Patent is:

1. The method of providing power which comprises burning the emulsioncomprising a nonaqueous thixotropic oily phase-in-nonoily phase emulsionfuel comprising (1) an emulsifia ble oily phase selected from the groupconsisting of animal oils, vegetable oils, mineral oils, resin oils andwood distillates, oils obtained from petroleum products, syntheticorganic esters, and natural organic esters, (2) a nonaqueous nonoilyphase selected from the group consisting of ethylene glycol, diethyleneglycol, propylene glycol, and dipropylene glycol, and (3) an emulsifyingagent, said emulsifiable oily phase being the internal phase and atleast by volume of the total emulsion, said emulsion having thecharacteristics of a solid when at rest and the characteristics of aliquid when a force is exerted upon it, said emulsion tending to benonadhesive, said emulsion having a critical shear point sufiicient topermit pumping at high rates, and said emulsion having an apparent restviscosity greater than about 1000 c.p.s. in a motor and utilizing theproducts of combustion as a source of power.

2. The method of claim 1 wherein said emulsion fuel also includes finelydivided combustible solids.

3. The method of claim 2 wherein said finely divided combustible solidis a metal.

4. The method of claim 3 wherein the products of combustion are used tocreate thrust in a reaction motor. 5. The method of claim 1 wherein saidoily phase is present in an amount of at least by volume of theemulsion.

6. The method of claim 5 wherein said emulsion also includes finelydivided combustible solids.

7. The method of claim 1 wherein said oily phase is a hydrocarbon.

8. The method of claim 2 wherein said oily phase is a hydrocarbon.

9. The method of claim 5 wherein the oily phase is a. hydrocarbon.

10. The method of claim 6 wherein the oily phase is a hydrocarbon.

References Cited UNITED STATES PATENTS 8/1968 Lissant et al 60-219 X 7/1969 Nixon et al. 44-51 BENJAMIN R. PADGETI, Primary Examiner

